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EP0404794A1 - Atomic absorption spectrometer. - Google Patents

Atomic absorption spectrometer.

Info

Publication number
EP0404794A1
EP0404794A1 EP89903130A EP89903130A EP0404794A1 EP 0404794 A1 EP0404794 A1 EP 0404794A1 EP 89903130 A EP89903130 A EP 89903130A EP 89903130 A EP89903130 A EP 89903130A EP 0404794 A1 EP0404794 A1 EP 0404794A1
Authority
EP
European Patent Office
Prior art keywords
light beam
sample
light source
measuring light
atomic absorption
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP89903130A
Other languages
German (de)
French (fr)
Other versions
EP0404794B1 (en
Inventor
Carl Guenther Dencks
Guenther Roedel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PE Manufacturing GmbH
Original Assignee
Bodenseewerk Perkin Elmer and Co GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bodenseewerk Perkin Elmer and Co GmbH filed Critical Bodenseewerk Perkin Elmer and Co GmbH
Priority to AT89903130T priority Critical patent/ATE81404T1/en
Publication of EP0404794A1 publication Critical patent/EP0404794A1/en
Application granted granted Critical
Publication of EP0404794B1 publication Critical patent/EP0404794B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/3103—Atomic absorption analysis
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/3103—Atomic absorption analysis
    • G01N2021/3111—Atomic absorption analysis using Zeeman split
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/256—Arrangements using two alternating lights and one detector
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/71—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light thermally excited
    • G01N21/74—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light thermally excited using flameless atomising, e.g. graphite furnaces

Definitions

  • the invention relates to an atomic absorption spectrometer containing
  • Atomic absorption spectrometers are used to determine the amount or concentration of an element in a sample.
  • a line of measurement light is directed from a line-emitting light source, for example a hollow cathode lamp, to a photoelectric detector.
  • An atomizing device is arranged in the beam path of this measuring light bundle.
  • the sample to be examined is atomized so that its components are in an atomic state.
  • the measuring light bundle contains the resonance lines of the element sought. These resonance lines of the measuring light beam are absorbed by the atoms of the element sought in the atomic cloud, while ideally the other elements contained in the sample do not influence the measuring light beam.
  • the measuring light beam is therefore weakened, which is a measure of the number of atoms of the element sought in the path of the measuring light beam and thus, depending on the atomization process used, a measure of the concentration or the amount of the element sought in the sample.
  • the absorption that the measuring light beam experiences is not only caused by the atoms of the element sought.
  • a flame, into which a sample is sprayed as a solution can serve as the atomizing device.
  • the electrothermal atomization is preferably used: the sample is placed in an oven which is heated to a high temperature by passing electric current through it.
  • the sample is first dried in the oven, then ashed and finally atomized.
  • An "atomic cloud” then forms in the furnace, in which the element sought is present in atomic form.
  • the measuring light beam is passed through this furnace.
  • These ovens can have different shapes. They are usually made from graphite.
  • a reference light bundle is passed through a flame or atomic cloud from a light source emitting a continuum with a wide bandwidth relative to the line width, the absorption of the measuring light bundle being caused by atomic absorption plus background absorption, while the absorption of the reference light beam is practically only determined by the background absorption.
  • Another method for determining the background absorption is based on the Zeeman effect: by applying a magnetic field to the sample, the absorption lines of the element sought in the sample are shifted in relation to the spectral 1 in lines of the measuring beam, so that in the sample no atomic absorption takes place in the applied magnetic field and only the background absorption is measured. By switching the magnetic field on and off, the absorption corrected atomic absorption can be measured.
  • the invention relates to an atomic absorption spectrometer in which the background absorption is determined by means of a reference light beam from a light source emitting a continuum.
  • atomic absorption - spectrometer known in which a Messler i 'chtbündel originates from a line-emitting light source, and is passed through a flame or a furnace for the electrothermal atomization onto a detector, and in which alternately containing this a line spectrum of a looked-for element measuring light beam a reference light beam from a light source emitting a continuum takes effect.
  • This reference light beam is reflected into the beam path of the measurement light beam by means of a beam splitter.
  • the beam splitter is usually a partially transparent mirror.
  • This mirror has evenly distributed reflecting and transmissive surface parts, so that 50% of the measurement light beam pass through the transmissive surface parts and 50% of the reference light beam is reflected on the reflecting surface parts in the direction of the measurement light bundle.
  • the change between measuring light bundle and reference light bundle is brought about in that the two light sources are switched on alternately.
  • each light beam is weakened by 50%. This leads to a deterioration in the signal-to-noise ratio, which can be critical for very sensitive measurements.
  • DE-AS 1 964 469 is an atomic absorption
  • Spectrometer known, in which the radiation emanates from a single radiation source designed as a line radiator, the radiation of which passes through the sample is frequency-modulated using the longitudinal Zeeman effect.
  • a hollow cathode lamp sits between the pole pieces of an electromagnet.
  • One of the pole pieces has a bore through which the measuring light beam passes.
  • the measuring light beam then passes through a flame serving as an atomizing device and a monochromator and falls on a photoelectric detector.
  • the electromagnet can be switched on and off, and the atomic absorption of the sample atoms, which is compensated for the background absorption, can be determined from the difference in the signals when the electromagnet is switched off and on.
  • the windings of the electromagnet sit there on the pole shoes.
  • the emission lines of the line-emitting light source are periodically shifted by the Zeeman effect and thus the emitted light is frequency-modulated and not the absorption lines of the sample.
  • a spectral line is split into a central line, the wavelength of which corresponds to the undisplaced wavelength of the line in question when the magnetic field is switched off, and two side lines which are shifted towards higher and lower wavelengths.
  • the central line and the side lines are polarized differently.
  • the influence of the central line can therefore be eliminated by a polarizer.
  • a polarizer results in 50% light loss.
  • the invention has for its object to allow greater flexibility with regard to the determination of the background absorption in a device of the type mentioned and, depending on the existing conditions, to ensure working with an optimal signal level.
  • this object is achieved in that (g) the beam splitter can optionally be moved out of the beam path.
  • the full unattenuated measuring light bundle can also be used, whereby the reference light bundle is not reflected. If the background absorption does not change particularly quickly, it is then also possible to carry out the measurement of the background absorption using the Zeeman effect, without the beam of measurement being additionally weakened by a beam splitter. When the longitudinal Zeeman effect is used, there is no absorption line at the location of the original line, so that the light attenuation required by the transverse Zeeman effect is also eliminated by a polarizer.
  • Embodiments of the invention are the subject of the dependent claims.
  • the figure shows schematically the structure of an atomic absorption spectroether, in which the background absorption is compensated for by utilizing the longitudinal Zeeman effect.
  • Preferred embodiment of the invention
  • the figure is a schematic representation of the atomic absorption spectrometer.
  • the atomic absorption spectrometer has a housing 10 in which the lamps, the optical system and the photosensitive detector are arranged.
  • the housing 10 forms a sample space 12.
  • An atomization device 14 is arranged in the sample space 12.
  • the atomic absorption spectrometer has a hollow cathode lamp 16 as a first light source 16.
  • the light source 16 emits a line spectrum that corresponds to the resonance lines of a specific, sought-after element.
  • a measuring light bundle 18 extends from the light source 16.
  • the measuring light beam 18 is deflected by a plane mirror 20 and collected by a concave mirror 22 through an opening 24 in the housing 10 in the middle of the sample space.
  • the measuring light beam then passes through an opening 26 of the housing 10 aligned with the opening 24 and falls on a second concave mirror 28. From the second concave mirror 28, the measuring light beam 18 is focused via a plane mirror 30 on the entry slit 32 of a monochromator 34.
  • a photoelectric detector 38 sits behind an exit gap 36 of the monochromator 34. The signal from the photoelectric detector 38 acts on a signal processing circuit 40.
  • the atomization device 14 contains a furnace for electrothermal atomization, of which only the actual furnace body 42 is shown in FIG. 1, and an electromagnet 44 that can be switched on and off for generation of a magnetic field at the location of the sample.
  • the electromagnet 44 has two aligned pole shoes 44 and 46, between which the furnace body 42 sits. Aligned bores 50 and 52 are provided in pole pieces 46 and 48. The bores 50 and 52 are aligned with a longitudinal bore 54 of the furnace body 42.
  • the measuring light beam 18 runs through the bores 50 and 52 and through the longitudinal bore of the furnace body.
  • Coil holders 56 and 58 are seated on pole pieces 50 and 52.
  • Coils 60 and 62 of electromagnet 44 are wound on these coil holders 56 and 58.
  • a power supply which controls the current through the furnace body 42. As indicated, the current is supplied transversely to the running direction of the measuring light bundle 18 and flows in the circumferential direction through the tubular furnace body 42.
  • the electromagnet 44 is controlled by a magnetic control 66, such that the magnetic field is alternately switched on and off.
  • the magnetic field of the electromagnet 44 extends at the location of the sample within the furnace body in the direction of travel of the measuring light beam 18.
  • the longitudinal Zeeman effect is therefore generated on the sample atoms. This means that the absorption lines of the sample atoms are split into two lines, which are shifted relative to the undisturbed original absorption line.
  • the atoms of the element sought no longer absorb the measuring light bundle 18, since this measuring light bundle only contains the unshifted resonance lines characteristic of the element.
  • the portion of the real atomic absorption corrected for the background absorption can be determined from the measurements with the magnetic field switched on and off.
  • the rhythm of the on and off circuit of the electromagnet 44 is for this purpose given to the signal evaluation circuit 40, as indicated by a line 68.
  • a second light source 70 which emits a continuum, is seated in the housing 10.
  • This second light source is a deuterium lamp.
  • the second light source 70 emits a light bundle 72.
  • This light bundle 72 from the second light source 70 can be pivoted into the beam path of the measurement beam 18 via a beam splitter 74 which can optionally be switched into the beam path.
  • the first and the second light sources 16 and 70 can be switched on alternately in rapid succession, so that alternately a measurement light bundle 18 with a line spectrum from the first light source (hollow cathode lamp) 16 or a measurement light bundle with a continuum from the second light source (deuterium lamp) through the atomic cloud formed in the furnace body.
  • the electromagnet is switched off.
  • the background absorption can then be determined by alternately measuring the absorption of the very narrow spectral 1 inle of the first light source and the absorption of a band of continuum radiation which is wide relative to the spectral 1 and determined by the monochromator 34.
  • the change between the first light source 16 and the second light source 70 takes place at a frequency of more than 500 Hertz, namely 1000 Hertz.
  • Working with a second light source emitting a continuum as the reference light source makes it possible to detect relatively rapid changes in the background absorption which cannot be detected when the Zeeman effect is used by means of the electromagnet 44.
  • the electromagnet 44 is relatively slow, so that the Frequency of the change between atomic absorption measurement and background measurement limits are set. By using the longitudinal Zeeman effect, no polarizer in the beam path is required. After the electromagnet has been switched off, the atomic absorption spectrometer can therefore work with a second light source 70 which emits a continuum, without double attenuation of light by a polarizer and additionally by the beam splitter 74.

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

Un spectromètre d'absorption atomique contient une première source lumineuse (16) émettant des lignes, et un système optique (20, 22, 28, 30, 34) pour créer un faisceau lumineux de mesure (18). Ce dernier passe à travers un espace d'échantillonnage (12) et heurte un détecteur photoélectrique (38). Un dispositif d'atomisation (14) est agencé dans l'espace d'échantillonnage pour l'atomisation d'un échantillon, de manière que les composantes de l'échantillon soient présentes sous forme atomique dans un espace d'atomisation traversé par le faisceau lumineux de mesure (18). Une seconde source de lumière (70) émettant un spectre continu est à l'origine d'un faisceau lumineux (72). Le faisceau lumineux de la seconde source lumineuse (70) est réfléchi par un fractionneur de rayons (74) sur la trajectoire des rayons du faisceau lumineux de mesure (18) et sert ainsi de faisceau lumineux de référence. Des moyens de branchement permettent de brancher les deux sources lumineuses (16, 70) alternativement. On peut, si on le souhaite, enlever le fractionneur de rayons (74) de la trajectoire des rayons. L'invention prévoit en outre un électro-aimant (44), qui crée un champ magnétique dans le sens du faisceau lumineux de mesure (18) là où se trouve l'échantillon atomisé et permet, facultativement, des mesures de fond spectral en vertu de l'effet Zeeman longitudinal.An atomic absorption spectrometer contains a first light source (16) emitting lines, and an optical system (20, 22, 28, 30, 34) for creating a measurement light beam (18). The latter passes through a sampling space (12) and collides with a photoelectric detector (38). An atomization device (14) is arranged in the sampling space for atomizing a sample, so that the components of the sample are present in atomic form in an atomization space crossed by the beam. measuring light (18). A second light source (70) emitting a continuous spectrum is the source of a light beam (72). The light beam of the second light source (70) is reflected by a ray splitter (74) on the path of the rays of the measurement light beam (18) and thus serves as a reference light beam. Connection means make it possible to connect the two light sources (16, 70) alternately. It is possible, if desired, to remove the beam splitter (74) from the beam path. The invention further provides an electromagnet (44), which creates a magnetic field in the direction of the measuring light beam (18) where the atomized sample is located and optionally allows spectral background measurements by virtue of of the longitudinal Zeeman effect.

Description

Ato absorptions - Spektro eter Ato absorption spectrometer
Technisches GebietTechnical field
Die Erfindung betrifft ein Atomabsorptions Spektrometer, enthaltendThe invention relates to an atomic absorption spectrometer containing
(a) eine linienemittierende erste ichtquel 1 le,(a) a line-emitting first light source,
(b) ein optisches System zur Erzeugung eines Meßlicht- bündeis, wobei dieses Meßlichtbündel durch einen(b) an optical system for producing a measuring light bundle, this measuring light bundle by a
Probenraum hindurchtritt und auf einen photo¬ elektrischen Detektor fällt,Sample space passes through and falls on a photoelectric detector,
(c) eine in dem Probenraum angeordnete Atomisierungs- einrichtung zur Atomisierung einer Probe, derart, daß die Bestandteile der Probe in einem v.on dem Meßlicht¬ bündel durchsetzten Atomisierungsbereich in atomarer Form vorliegen,(c) an atomization device arranged in the sample space for atomizing a sample, such that the constituents of the sample are present in atomic form in an atomization area penetrated by the measuring light beam,
(d) eine ein Kontinuum emittierende zweite Lichtquelle, von der ein Lichtbündel ausgeht, (e) ein Strahlenteiler, durch welchen das Lichtbündel von der zweiten Lichtquelle als Referenzlichtbündel in den Strahlengang des Meßlichtbündels (18) einspiegelbar ist, und(d) a second light source emitting a continuum from which a light beam emanates, (e) a beam splitter through which the light beam from the second light source can be reflected as a reference light beam into the beam path of the measuring light beam (18), and
(f) Einschaltmittel, durch welche die beiden Lichtquellen (16,70) alternierend einschaltbar sind,(f) switch-on means by which the two light sources (16, 70) can be switched on alternately,
Atomabsorptions - Spektrometer dienen zur Bestimmung der Menge oder Konzentration eines gesuchten Elementes in einer Probe-. Zu diesem Zweck wird von einer linien¬ emittierenden Lichtquelle, beispielsweise einer Hohl- kathodenlampe, ein Meßlichtbündel auf einen photo¬ elektrischen Detektor geleitet. Im Strahlengang dieses Meßlichtbündels ist eine Atomisierungsvorrichtung angeordnet. In dieser Atomisierungsvorrichtung wird die zu untersuchende Probe atomisiert, so daß ihre Bestandteile in atomarem Zustand vorliegen. Das Meßlichtbündel enthält die Resonanzlinien des gesuchten Elements. Diese Resonanz¬ linien des Meßlichtbündels werden von den Atomen des gesuchten Elements in der Atomwolke absorbiert, während im Idealfall die anderen in der Probe enthaltenen Elemente das Meßlichtbündel nicht beeinflußen. Das Meßlichtbündel erfährt daher eine Schwächung, die ein Maß für die Anzahl der im Weg des Meßlichtbündels befindlichen Atome des gesuchten Elements und damit je nach dem angewandten Atomisierungsverfahren ein-Maß für die Konzentration oder die Menge des gesuchten Elementes in der Probe darstellt. Die Absorption, die das Meßlichtbündel erfährt, wird aber nicht nur durch die Atome des gesuchten Elements hervorgerufen. Es gibt eine "Untergrundabsorption" * beispielsweise infolge der Absorption des Lichts durch Moleküle. Diese Untergrundabsorption muß insbesondere bei hochempfindlichen Messungen kompensiert werden. Als Atomisierungsvorrichtung kann eine Flamme dienen, in welche eine Probe als Lösung eingesprüht wird. Für hoch¬ empfindliche Messungen verwendet man aber vorzugsweise die elektrother i sehe Atomi s ierung : Die Probe wird in einen Ofen eingebracht, der durch Hindurchleiten von elektrischem Strom auf eine hohe Temperatur aufgeheizt wird. Dadurch wird die Probe in dem Ofen zunächst getrocknet, dann verascht und schließlich atomisiert. In dem Ofen bildet sich dann eine "Atomwolke" aus, in welcher das gesuchte Element in atomarer Form vorliegt. Das Meßlichtbündel wird durch diesen Ofen hindurchgeleitet. Diese Öfen können verschiedene Form haben. Sie werden üblicherweise aus Graphit hergestellt.Atomic absorption spectrometers are used to determine the amount or concentration of an element in a sample. For this purpose, a line of measurement light is directed from a line-emitting light source, for example a hollow cathode lamp, to a photoelectric detector. An atomizing device is arranged in the beam path of this measuring light bundle. In this atomization device, the sample to be examined is atomized so that its components are in an atomic state. The measuring light bundle contains the resonance lines of the element sought. These resonance lines of the measuring light beam are absorbed by the atoms of the element sought in the atomic cloud, while ideally the other elements contained in the sample do not influence the measuring light beam. The measuring light beam is therefore weakened, which is a measure of the number of atoms of the element sought in the path of the measuring light beam and thus, depending on the atomization process used, a measure of the concentration or the amount of the element sought in the sample. The absorption that the measuring light beam experiences is not only caused by the atoms of the element sought. There is "background absorption" *, for example, due to the absorption of light by molecules. This background absorption must be compensated in particular for highly sensitive measurements. A flame, into which a sample is sprayed as a solution, can serve as the atomizing device. For highly sensitive measurements, however, the electrothermal atomization is preferably used: the sample is placed in an oven which is heated to a high temperature by passing electric current through it. As a result, the sample is first dried in the oven, then ashed and finally atomized. An "atomic cloud" then forms in the furnace, in which the element sought is present in atomic form. The measuring light beam is passed through this furnace. These ovens can have different shapes. They are usually made from graphite.
Zur Bestimmung und Kompensation der Untergrundabsorption werden im wesentlichen zwei Verfahren angewandt. Einmal wird abwechselnd mit dem Meßlichtbündel von der linien¬ emittierenden Lichtquelle ein Referenzlichtbündel von einer ein Kontinuum emittierenden Lichtquelle mit einer relativ zu der Linienbreite großen Bandbreite durch die Flamme oder Atomwolke geleitet, wobei die Absorption des Meßlichtbündels durch Atomabsorption plus Untergrund¬ absorption hervorgerufen wird, während die Absorption des Referenzlichtbündels praktisch nur durch die Untergrund- absorption bestimmt ist.Essentially two methods are used to determine and compensate for the background absorption. On the one hand, alternately with the measuring light bundle from the line-emitting light source, a reference light bundle is passed through a flame or atomic cloud from a light source emitting a continuum with a wide bandwidth relative to the line width, the absorption of the measuring light bundle being caused by atomic absorption plus background absorption, while the absorption of the reference light beam is practically only determined by the background absorption.
Ein anderes Verfahren zur Bestimmung der Untergrund¬ absorption beruht auf dem Zeeman - Effekt: Durch Anlegen eines Magnetfeldes an die Probe werden die Absorptions- linien des gesuchten Elements in der Probe gegenüber den Spektral 1 in ien des Meßstrahlenbündels verschoben, so daß in der Probe bei anliegendem Magnetfeld keine Atomabsorption stattfindet und nur die Untergrund¬ absorption gemessen wird. Durch Ein- und Ausschalten des Magnetfeldes kann dann die hinsichtlich Untergrund- absorption korrigierte Atomabsorption gemessen werden.Another method for determining the background absorption is based on the Zeeman effect: by applying a magnetic field to the sample, the absorption lines of the element sought in the sample are shifted in relation to the spectral 1 in lines of the measuring beam, so that in the sample no atomic absorption takes place in the applied magnetic field and only the background absorption is measured. By switching the magnetic field on and off, the absorption corrected atomic absorption can be measured.
Die Erfindung betrifft ein Atomabsorptions - Spektrometer, bei welchem die Untergrundabsorption mittels eines Referenzlichtbündels von einer ein Kontinuum emittierenden Lichtquelle bestimmt wird.The invention relates to an atomic absorption spectrometer in which the background absorption is determined by means of a reference light beam from a light source emitting a continuum.
Zugrundeliegender Stand der Technik.Underlying state of the art.
Es sind Atomabsorptions - Spektrometer bekannt, bei denen von einer linienemittierenden Lichtquelle ein Meßl i'chtbündel ausgeht und durch eine Flamme oder einen Ofen für die elektrothermische Atomisierung hindurch auf einen Detektor geleitet wird, und bei welchem alternierend mit diesem ein Linienspektrum eines gesuchten Elements enthaltenden Meßlichtbündel ein Referenzlichtbündel von einer ein Kontinuum emittierenden Lichtquelle wirksam wird. Dieses Referenzlichtbündel wird mittels einees Strahlenteilers in den Strahlengang des Meßlichtbündels eingespiegelt. Der Strahlenteiler ist dabei üblicherweise ein teildurchlässiger Spiegel. Dieser Spiegel weist gleichmäßig verteilt spiegelnde und durchlässige Flächen¬ teile auf, so daß 50% des Meßlichtbündels durch die durchlässigen Flächenteile hindurchtreten und 50% des Referenzlichtbündels an den spiegelnden Flächenteilen in Richtung -des Meßlichtbündels reflektiert werden. Der Wechsel zwischen Meßlichtbündel und Referenzlichtbündel wird dadurch bewirkt, daß die beiden Lichtquellen alternierend eingeschaltet werden.There are atomic absorption - spectrometer known in which a Messler i 'chtbündel originates from a line-emitting light source, and is passed through a flame or a furnace for the electrothermal atomization onto a detector, and in which alternately containing this a line spectrum of a looked-for element measuring light beam a reference light beam from a light source emitting a continuum takes effect. This reference light beam is reflected into the beam path of the measurement light beam by means of a beam splitter. The beam splitter is usually a partially transparent mirror. This mirror has evenly distributed reflecting and transmissive surface parts, so that 50% of the measurement light beam pass through the transmissive surface parts and 50% of the reference light beam is reflected on the reflecting surface parts in the direction of the measurement light bundle. The change between measuring light bundle and reference light bundle is brought about in that the two light sources are switched on alternately.
Bei dieser bekannten Anordnung wird jedes Lichtbündel um 50% geschwächt. Das führt zu einer Verschlechterung des Signal - zu - Rausch - Verhältnisses, was bei sehr empfindlichen Messungen kritisch sein kann. Durch die DE-AS 1 964 469 ist ein AtomabsorptionsIn this known arrangement, each light beam is weakened by 50%. This leads to a deterioration in the signal-to-noise ratio, which can be critical for very sensitive measurements. DE-AS 1 964 469 is an atomic absorption
Spektrometer bekannt, bei welchem die Strahlung von einer einzigen, als Linienstrahler ausgebildeten Strahlungs¬ quelle ausgeht, deren durch die Probe tretende Strahlung unter Ausnutzung des longitudinalen Zeeman - Effektes frequenzmoduliert wird. Bei diesem bekannten Atom¬ absorptions - Spektrometer sitzt eine Hohlkathodenlampe zwischen den Polschuhen eines Elektromagneten. Einer der Polschuhe weist eine Bohrung auf, durch welche das Meßlichtbündel hindurchtritt. Das Meßlichtbündel tritt dann durch eine als Atomisierungsvorrichtung dienende Flamme und einen Monochromator und fällt auf einen Photoelektrischen Detektor. Der Elektromagnet ist ein- und ausschaltbar, wobei aus der Differenz der Signale bei aus- und eingeschaltetem Elektromagneten die atomare, hinsichtlich der Untergrundabsorption kompensierte Absorption der Probenatome bestimmt werden kann. Die Wicklungen des Elektromagneten sitzen dort auf den Pol¬ schuhen .Spectrometer known, in which the radiation emanates from a single radiation source designed as a line radiator, the radiation of which passes through the sample is frequency-modulated using the longitudinal Zeeman effect. In this known atomic absorption spectrometer, a hollow cathode lamp sits between the pole pieces of an electromagnet. One of the pole pieces has a bore through which the measuring light beam passes. The measuring light beam then passes through a flame serving as an atomizing device and a monochromator and falls on a photoelectric detector. The electromagnet can be switched on and off, and the atomic absorption of the sample atoms, which is compensated for the background absorption, can be determined from the difference in the signals when the electromagnet is switched off and on. The windings of the electromagnet sit there on the pole shoes.
Bei dem bekannten Atomabsorptions - Spektrometer werden die Emissionslinien der linienemittierenden Lichtquelle durch den Zeeman - Effekt periodisch verschoben und damit das emittierte Licht frequenzmoduliert und nicht die Absorptionslinien der Probe.In the known atomic absorption spectrometer, the emission lines of the line-emitting light source are periodically shifted by the Zeeman effect and thus the emitted light is frequency-modulated and not the absorption lines of the sample.
Durch die DE-PS 2 165 106 ist es bekannt, das Magnetfeld eines ein- und ausschaltbaren Elektromagneten statt an die Lichtquelle an die Atomisierungsvorrichtung anzulegen, also an die atomisierte Probe. Die Atomisierungs¬ vorrichtung ist dabei eine Flamme. Das Magnetfeld wird senkrecht zur Laufrichtung des Meßlichtbündels angelegt. Es erfolgt hier eine Aufspaltung der Absorptionslinien infolge des "transversalen" Zeeman - Effektes, was wiederum eine Relativverschiebung der Emissionslinien des Meßlichtbündels und der Absorptionslinien der Probe bewirkt. Durch Ein- und Auschalten des Magnetfeldes kann wieder zwischen atomarer Absorption durch die Atome des gesuchten Elements und unspezifischer Untergrundabsorption unterschieden werden.From DE-PS 2 165 106 it is known to apply the magnetic field of an electromagnet that can be switched on and off instead of to the light source on the atomizing device, that is to say on the atomized sample. The atomizing device is a flame. The magnetic field is applied perpendicular to the direction of travel of the measuring light beam. Here, the absorption lines are split up as a result of the "transverse" Zeeman effect, which in turn causes a relative shift in the emission lines of the Measurement light beam and the absorption lines of the sample causes. By switching the magnetic field on and off, a distinction can again be made between atomic absorption by the atoms of the element sought and non-specific background absorption.
Bei der Anwendung des transversalen Zeeman - Effektes erfolgt die Aufspaltung einer Spektral 1 inie in eine zentrale Linie, deren Wellenlänge der - unverschobenen Wellenlänge der betreffenden Linie bei abgeschaltetem Magnetfeld entspricht, und zwei demgegenüber zu höheren und zu niedrigeren Wellenlängen hin verschobenen Seiten¬ linien. Die zentrale Linie und die Seitenlinien sind unterschiedlich polarisiert. Man kann daher den Einfluß der zentralen Linie durch einen Polarisator eliminieren. Ein solcher Polarisator bringt jedoch einen Lichtverlust von 50%.When using the transverse Zeeman effect, a spectral line is split into a central line, the wavelength of which corresponds to the undisplaced wavelength of the line in question when the magnetic field is switched off, and two side lines which are shifted towards higher and lower wavelengths. The central line and the side lines are polarized differently. The influence of the central line can therefore be eliminated by a polarizer. However, such a polarizer results in 50% light loss.
Die Kompensation der Untergrundabsorption durch Anwendung des Zeeman - Effektes kann zu Schwierigkeiten führen, wenn sich die Untergrundabsorption schnell ändert, da der Frequenz des Ein- und Auschaltens des Magnetfeldes infolge der Selbstinduktion des Elektromagneten Grenzen gesetzt sind.Compensation of the background absorption by using the Zeeman effect can lead to difficulties if the background absorption changes rapidly, since the frequency of the switching on and off of the magnetic field is limited due to the self-induction of the electromagnet.
Offenbarung der ErfindungDisclosure of the invention
Der Erfindung liegt die Aufgabe zugrunde, bei einem Gerät der eingangs genannten Art eine größere Flexibilität hinsichtlich der Bestimmung der Untergrundabsorption zu ermöglichen und je nach den vorliegenden Verhältnissen ein Arbeiten mit optimalem Signalpegel zu gewährleisten.The invention has for its object to allow greater flexibility with regard to the determination of the background absorption in a device of the type mentioned and, depending on the existing conditions, to ensure working with an optimal signal level.
Erfindungsgemäß wird diese Aufgabe dadurch gelöst, daß (g) der Strahlenteiler wahlweise aus dem Strahlengang herausbewegbar ist.According to the invention this object is achieved in that (g) the beam splitter can optionally be moved out of the beam path.
Es kann dann wahlweise mit Messung und Kompensation der Untergrundabsorption mittels der ein Kontinuum emittierenden Lichtquelle gearbeitet werden, wobei eine Schwächung des Meßlichtbündels in Kauf genommen wird. Es kann aber, z.B. zur Erzielung hoher Empfindlichkeit bei weniger störendem Untergrund, auch das volle ungeschwächte Meßlichtbündel ausgenutzt werden, wobei auf eine Ein- spiegelung des Referenzlichbündels verzichtet wird. Es ist dann auch möglich, wenn sich die Untergrundabsorption nicht besonders schnell ändert, die Messung • der Untergrundabsorption unter Ausnutzung des Zeeman Effektes vorzunehmen, ohne daß dabei das Meßlichtbündel durch einen Strahlenteiler zusätzlich geschwächt wird. Bei Anwendung des longitudinalen Zeeman - Effektes tritt am Ort der ursprünglichen Linie keine Absorptionslinie auf, so daß auch die beim transversalen Zeeman - Effekt erforderliche Lichtschwächung durch einen Polarisator entfäl lt.It is then optionally possible to work with measurement and compensation of the background absorption by means of the light source emitting a continuum, with a weakening of the measuring light beam being accepted. However, e.g. In order to achieve high sensitivity with less disturbing background, the full unattenuated measuring light bundle can also be used, whereby the reference light bundle is not reflected. If the background absorption does not change particularly quickly, it is then also possible to carry out the measurement of the background absorption using the Zeeman effect, without the beam of measurement being additionally weakened by a beam splitter. When the longitudinal Zeeman effect is used, there is no absorption line at the location of the original line, so that the light attenuation required by the transverse Zeeman effect is also eliminated by a polarizer.
Ausgestaltungen der Erfindung sind Gegenstand der Unteransprüche.Embodiments of the invention are the subject of the dependent claims.
Ein Ausführungsbeispiel der Erfindung ist nachstehend unter Bezugnahme auf die zugehörigen Zeichnungen näher erläutert.An embodiment of the invention is explained below with reference to the accompanying drawings.
Kurze Beschreibung der ZeichnungBrief description of the drawing
Die Figur zeigt schematisch den Aufbau eines Atom¬ absorptions - Spektro eters , bei welchem die Untergrund¬ absorption durch Ausnutzung des longitudinalen Zeeman • Effektes kompensiert wird. Bevorzugte Ausführung der ErfindungThe figure shows schematically the structure of an atomic absorption spectroether, in which the background absorption is compensated for by utilizing the longitudinal Zeeman effect. Preferred embodiment of the invention
Die Figur ist eine schematische Darstellung des Atomabsorptions - Spektro eters .The figure is a schematic representation of the atomic absorption spectrometer.
Das Atomabsorptions - Spektrometer weist ein Gehäuse 10 auf, in welchem die Lampen, das optische System und der photoempfindliche Detektor angeordnet sind. Das Gehäuse 10 bildet einen Probenraum 12. In dem Probenraum 12 ist eine Atomisierungsvorrichtung 14 angeordnet.The atomic absorption spectrometer has a housing 10 in which the lamps, the optical system and the photosensitive detector are arranged. The housing 10 forms a sample space 12. An atomization device 14 is arranged in the sample space 12.
Das Atomabsorptions - Spektrometer weist als eine erste Lichtquelle 16 eine Hohlkathodenlampe 16 auf. Die Lichtquelle 16 emittiert ein Linienspektrum, das den Resonaπzlinien eines bestimmten, gesuchten Elements entspricht. Von der Lichtquelle 16 geht ein Meßlichtbündel 18 aus. Das Meßlichtbündel 18 wird von einem Planspiegel 20 umgelenkt und von- einem Hohlspiegel 22 durch eine Öffnung 24 des Gehäuses 10 hindurch in der Mitte des Probenraumes gesammelt. Das Meßlichtbündel tritt dann durch eine mit der Öffnung 24 fluchtenden Öffnung 26 des Gehäuses 10 und fällt auf einen zweiten Hohlspiegel 28. Von dem zweiten Hohlspiegel 28 wird das Meßlichtbündel 18 über einen Planspiegel 30 auf dem Eintrittsspalt 32 eines Monochromators 34 fokussiert. Hinter einem Austrittsspalt 36 des Monochromators 34 sitzt ein photoelektrtscher Detektor 38. Das Signal des photoelektrischen Detektors 38 beaufschlagt eine Signalverarbeitungs - Schaltung 40.The atomic absorption spectrometer has a hollow cathode lamp 16 as a first light source 16. The light source 16 emits a line spectrum that corresponds to the resonance lines of a specific, sought-after element. A measuring light bundle 18 extends from the light source 16. The measuring light beam 18 is deflected by a plane mirror 20 and collected by a concave mirror 22 through an opening 24 in the housing 10 in the middle of the sample space. The measuring light beam then passes through an opening 26 of the housing 10 aligned with the opening 24 and falls on a second concave mirror 28. From the second concave mirror 28, the measuring light beam 18 is focused via a plane mirror 30 on the entry slit 32 of a monochromator 34. A photoelectric detector 38 sits behind an exit gap 36 of the monochromator 34. The signal from the photoelectric detector 38 acts on a signal processing circuit 40.
Die Atomisierungsvorrichtung 14 enthält einen Ofen zur elektrothermischen Atomisierung, von welchem in Fig.1 nur der eigentliche Ofenkörper 42 dargestellt ist, und einen ein- und ausschaltbaren Elektromagneten 44 zur Erzeugung eines Magnetfeldes am Ort der Probe. Der Elektromagnet 44 weist zwei fluchtende Polschuhe 44 und 46 auf, zwischen denen der Ofenkörper 42 sitzt. In den Polschuhen 46 und 48 sind fluchtende Bohrungen 50 und 52 angebracht. Die Bohrungen 50 und 52 fluchten mit einer Längsbohrung 54 des Ofenkörpers 42. Das Meßlichtbündel 18 verläuft durch die Bohrungen 50 und 52 und durch die Längsbohrung des Ofenkörpers. Auf den Polschuhen 50 und 52 sitzen Spulen- halterungen 56 bzw. 58. Auf diese Spulenhaiterungen 56 und 58 sind Spulen 60 bzw. 62 des Elektromagneten 44 gewickelt. Mit 64 ist ein Netzteil bezeichnet, welches den Strom durch den Ofenkörper 42 steuert. Wie angedeutet, wird der Strom quer zur Laufrichtung de-s Meßlichtbündels 18 zugeführt und fließt in Umfangsrichtung durch den rohrförmigen Ofenkörper 42. Der Elektromagnet 44 ist von einer Magnetsteueruπg 66 gesteuert, derart, daß das Magnetfeld abwechselnd ein- und ausgeschaltet wird. Das Magnetfeld des Elektromagneten 44 verläuft am Ort der Probe innerhalb des Ofenkörpers in Laufrichtung des Meßlichtbündels 18. Bei eingeschaltetem Magnetfeld wird daher an den Probeπatomen der longitudinale Zeeman Effekt erzeugt. Das bedeutet, daß die Absorptions 1 inien der Probenatome in jeweils zwei Linien aufgespalten werden, die gegenüber der ungestörten ursprünglichen Absorptionslinie verschoben sind. Bei der Wellenlänge der ursprünglichen Absorptionslinie erfolgt keine atomare Absorption in der Probe mehr. Daher absorbieren auch die Atome des gesuchten Elements das Meßlichtbündel 18 nicht mehr, da dieses Meßlichtbündel nur die unverschobenen für das Element charakteristischen Resonanzlinien enthält. Bei eingeschaltetem Magnetfeld wird daher nur die Untergrund¬ absorption gemessen. Aus den Messungen bei ein- und ausgeschaltetem Magnetfeld kann der hinsichtlich der Untergrundabsorption korrigierte Anteil der echten Atom- absorption bestimmt werden. Der Takt der Ein- und Aus- schaltung des Elektromagneten 44 wird zu diesem Zweck auf die Signalauswertungs - Schaltung 40 gegeben, wie durch eine Leitung 68 angedeutet ist. Durch die Anwendung des longitudinalen Zeeman - Effektes wird ein Polarisator im Strahlengang entbehrlich und das Nutzsignal verbessert.The atomization device 14 contains a furnace for electrothermal atomization, of which only the actual furnace body 42 is shown in FIG. 1, and an electromagnet 44 that can be switched on and off for generation of a magnetic field at the location of the sample. The electromagnet 44 has two aligned pole shoes 44 and 46, between which the furnace body 42 sits. Aligned bores 50 and 52 are provided in pole pieces 46 and 48. The bores 50 and 52 are aligned with a longitudinal bore 54 of the furnace body 42. The measuring light beam 18 runs through the bores 50 and 52 and through the longitudinal bore of the furnace body. Coil holders 56 and 58 are seated on pole pieces 50 and 52. Coils 60 and 62 of electromagnet 44 are wound on these coil holders 56 and 58. With 64 a power supply is designated, which controls the current through the furnace body 42. As indicated, the current is supplied transversely to the running direction of the measuring light bundle 18 and flows in the circumferential direction through the tubular furnace body 42. The electromagnet 44 is controlled by a magnetic control 66, such that the magnetic field is alternately switched on and off. The magnetic field of the electromagnet 44 extends at the location of the sample within the furnace body in the direction of travel of the measuring light beam 18. When the magnetic field is switched on, the longitudinal Zeeman effect is therefore generated on the sample atoms. This means that the absorption lines of the sample atoms are split into two lines, which are shifted relative to the undisturbed original absorption line. At the wavelength of the original absorption line, there is no longer any atomic absorption in the sample. Therefore, the atoms of the element sought no longer absorb the measuring light bundle 18, since this measuring light bundle only contains the unshifted resonance lines characteristic of the element. When the magnetic field is switched on, only the background absorption is measured. The portion of the real atomic absorption corrected for the background absorption can be determined from the measurements with the magnetic field switched on and off. The rhythm of the on and off circuit of the electromagnet 44 is for this purpose given to the signal evaluation circuit 40, as indicated by a line 68. By using the longitudinal Zeeman effect, a polarizer in the beam path is not necessary and the useful signal is improved.
In dem Gehäuse 10 sitzt eine zweite Lichtquelle 70, die ein Kontinuum emittiert. Diese zweite Lichtquelle ist eine Deuteriumlampe. Die zweite Lichtquelle 70 sendet ein Lichtbündel 72 aus. Dieses Lichtbündel 72 von der zweiten Lichtquelle 70 kann über einen in den Strahlengang wahlweise einschaltbaren Strahlenteiler 74 in den Strahlengang des Meß.1 ichtbündels 18 eingeschwenkt werden. Die erste und die zweite Lichtquelle 16 bzw. 70 können in schneller Folge abwechselnd eingeschaltet werden, so daß abwechselnd ein Meßlichtbündel 18 mit einem Linienspektrum von der ersten Lichtquelle (Hohlkathodenlampe) 16 oder ein Meßlichtbündel mit einem Kontinuum von der zweiten Lichtquelle (Deuteriuml-ampe) durch die in dem Ofenkörper gebildete Atomwolke tritt. Bei dieser Betriebsweise mit eingeschaltetem Strahlenteiler 74 ist der Elektromagnet ausgeschaltet. Die Untergrundabsorption kann dann dadurch bestimmt werden, daß abwechselnd die Absorption der sehr schmalen Spektral 1 inle der ersten Lichtquelle und die Absorption eines relativ zu der Spektral 1 inie breiten, durch den Monochromator 34 bestimmten Bandes von Kontinuumsstrahlung gemessen wird. Der Wechsel zwischen der ersten Lichtquelle 16 und der zweiten Lichtquelle 70 erfolgt mit einer Frequenz von mehr als 500 Hertz, nämlich 1000 Hertz. Die Arbeitsweise mit einer ein Kontinuum emittierenden zweiten Lichtquelle als Referenzlichtquelle gestattet es, relativ schnelle Änderungen der Untergrund¬ absorption zu erfassen, die bei der Ausnutzung des Zeeman- Effekts mittels des Elektromagneten 44 nicht erfaßt werden können. Der Elektromagnet 44 ist relativ träge, so daß der Frequenz des Wechsels zwischen Atomabsorptionsmessung und Untergrundmessung Grenzen gesetzt sind. Durch die Anwendung des longitudinalen Zeeman - Effektes ist kein Polarisator im Strahlengang erforderlich. Nach Abschaltung des Elektromagneten kann daher das Atomabsorptions Spektrometer mit einer ein Kontinuum emittierenden zweiten Lichtquelle 70 arbeiten, ohne daß eine doppelte Lichtschwächung durch einen Polarisator und zusätzlich durch den Strahlenteiler 74 erfolgen würde.A second light source 70, which emits a continuum, is seated in the housing 10. This second light source is a deuterium lamp. The second light source 70 emits a light bundle 72. This light bundle 72 from the second light source 70 can be pivoted into the beam path of the measurement beam 18 via a beam splitter 74 which can optionally be switched into the beam path. The first and the second light sources 16 and 70 can be switched on alternately in rapid succession, so that alternately a measurement light bundle 18 with a line spectrum from the first light source (hollow cathode lamp) 16 or a measurement light bundle with a continuum from the second light source (deuterium lamp) through the atomic cloud formed in the furnace body. In this mode of operation with the beam splitter 74 switched on, the electromagnet is switched off. The background absorption can then be determined by alternately measuring the absorption of the very narrow spectral 1 inle of the first light source and the absorption of a band of continuum radiation which is wide relative to the spectral 1 and determined by the monochromator 34. The change between the first light source 16 and the second light source 70 takes place at a frequency of more than 500 Hertz, namely 1000 Hertz. Working with a second light source emitting a continuum as the reference light source makes it possible to detect relatively rapid changes in the background absorption which cannot be detected when the Zeeman effect is used by means of the electromagnet 44. The electromagnet 44 is relatively slow, so that the Frequency of the change between atomic absorption measurement and background measurement limits are set. By using the longitudinal Zeeman effect, no polarizer in the beam path is required. After the electromagnet has been switched off, the atomic absorption spectrometer can therefore work with a second light source 70 which emits a continuum, without double attenuation of light by a polarizer and additionally by the beam splitter 74.
Es ist aber auch möglich, den Elektromagneten 44 abzuschalten und gleichzeitig den Strahlenteiler 74 aus dem Strahlengang herauszubewegen. In diesem Fall wird ohne Untergrundkompensation aber mit voller Intensität des Meßlichtbündels gearbeitet. However, it is also possible to switch off the electromagnet 44 and at the same time to move the beam splitter 74 out of the beam path. In this case, work is carried out without background compensation but with full intensity of the measuring light beam.

Claims

Patentansprüche Claims
1. Atomabsorptions - Spektrometer, enthaltend1. Atomic absorption spectrometer containing
(a) eine linienemittiereπde erste Lichtquellle (16),(a) a line-emitting first light source (16),
(b) ein optisches System (20,22,28,30,34) zur(b) an optical system (20,22,28,30,34) for
Erzeugung eines Meßlichtbündels (18), wobei dieses Meßlichtbündel (18) durch einen Probenraum . (12) hindurchtritt und auf einen photo¬ elektrischen Detektor (38) fällt,Generation of a measuring light beam (18), this measuring light beam (18) through a sample space. (12) passes through and falls on a photoelectric detector (38),
(c) eine in dem Probenraum angeordnete Atomisierungs- einrichtung (14) zur Atomisierung einer Probe, derart, daß die Bestandteile der Probe in einem von dem Meßlichtbündel (18) durchsetzten Ato i- sierungsbereich in atomarer Form vorliegen,(c) an atomization device (14) arranged in the sample space for atomizing a sample such that the constituents of the sample are present in atomic form in an atomization area penetrated by the measuring light beam (18),
(d) eine ein Kontinuum emittierende zweite Lichtquelle (70), von der ein Lichtbündel (72) ausgeht,(d) a second light source (70) emitting a continuum, from which a light beam (72) originates,
(e) einen Strahlenteiler (74), durch welchen das(e) a beam splitter (74) through which the
Lichtbündel von der zweiten Lichtquelle (70) alsBeam of light from the second light source (70) as
Ref renzlichtbündel in den Strahlengang des Meßlichtbündels (18) einspiegelbar ist, undRef renzlichtbündels in the beam path of the measuring light beam (18) can be reflected, and
(f) Eiπschaltmittel , durch welche die beiden Licht¬ quellen (16,70) alternierend einschaltbar sind, dadurch gekennzeichnet, daß(f) switching means by which the two light sources (16, 70) can be switched on alternately, characterized in that
(g) der Strahlenteiler (74) wahlweise aus dem Strahleπgang herausbewegbar ist.(g) the beam splitter (74) can optionally be moved out of the beam path.
2. Atomabsorptions - Spektrometer nach Anspruch 1 , gekennzeichnet durch eine zusätzliche Einrichtung zur gegenseitigen Verschiebung der Spektal 1 inien des Me߬ lichtbündels und der Absorptionslinien des gesuchten Elements in der Probe mit Hilfe des Zeeman Effektes.2. Atomic absorption spectrometer according to claim 1, characterized by an additional device for mutually displacing the spectral 1 lines of the measuring light beam and the absorption lines of the sought element in the sample with the aid of the Zeeman effect.
3. Atomabsorptions - Spektrometer nach Anspruch 2, dadurch gekennzeichnet, daß die besagte Einrichtung von einem ein- und ausschaltbaren Elektromagneten gebildet ' ist, der ein Magnetfeld am Ort der atomisierten Probe erzeugt.3. Atomic Absorption - A spectrometer according to claim 2, characterized in that said means is constituted by a switched on and off electromagnets' generates a magnetic field at the location of the atomized sample.
4. Atomabsorptions - Spektrometer nach Anspruch 3, dadurch gekennzeichnet, daß das von dem Elektro¬ magneten erzeugte Magnetfeld parallel zur Richtung des Meßlichtbündels verläuft, so daß eine Linienaufspaltung durch den longitudinalen Zeeman - Effekt eintritt. 4. Atomic absorption spectrometer according to claim 3, characterized in that the magnetic field generated by the electro-magnet runs parallel to the direction of the measuring light beam, so that a line splitting occurs due to the longitudinal Zeeman effect.
EP89903130A 1988-03-18 1989-03-13 Atomic absorption spectrometer Expired - Lifetime EP0404794B1 (en)

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AT89903130T ATE81404T1 (en) 1988-03-18 1989-03-13 ATOMIC ABSORPTION SPECTROMETER.

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DE3809213 1988-03-18
DE3809213A DE3809213A1 (en) 1988-03-18 1988-03-18 ATOMIC ABSORPTION SPECTROMETER

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AU624608B2 (en) 1992-06-18
AU3352189A (en) 1989-10-05
EP0404794B1 (en) 1992-10-07
DE58902429D1 (en) 1992-11-12
JPH04501602A (en) 1992-03-19
DE3809213A1 (en) 1989-10-05
US5181077A (en) 1993-01-19
WO1989008832A1 (en) 1989-09-21
JP3047104B2 (en) 2000-05-29

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